Electrical plug and socket.



J. McELROY, DECID.

S. H. MCELROY, EXECUTRIX.

ELECTRLCAL PLUG AND SOCKET.

APPLICATION FILED FEB. 27. 1912.

mawm PatentedJune 5,1917.

WITNESSES: INVENTOR vll' it F. MUELEOY, F ALBANY, NEW YORK; SUSIE H. MQELROY, EXECUTBIX 0F SAID JAMES F. MOELBOY, DECEASED, ASSIGNOR TO CONSOLIDATED CAR-HEATING- COM- A CUEPORATION OF WEST VIRGINIA.

' ELECTRICAL PLUG AND SOCKET.

T,@28,5'?, I Specification of Letters Patent.

Patented June 5, 191?.

Application filed February 27, 1912. Serial No. 680,232.

To all whom it may concern.

Be it known that I, JAMES F. MoELRox, a citizen of the United States, residing at Albany, county of Albany, State of New York, have invented certain new and useful Improvements in Electrical Plugs and Sockets, the following being a full, clear,

" and exact disclosure of theone form of my invention which I at present deem preferable.

For a detailed description of the present form of my invention, reference may be had to the following specification and to the aceompanying drawing, which illustrates my invention.

Figure 1 is an elevation, partly in section,

of the plug;

s ective faces of the plug Fig. 2 is a transverse'section of Fig. 1;

Fig. 3 is a front elevation and Fig. 4 is a side elevation of the socketcasing without the plug;

Fig. 5 is a front elevation and Fig. 6 aside elevation of the socket-casing with the plug inserted;

' Igig. 7 is a horizontal section of the socket an Fig. 8 a vertical section of the same with Y the plug in place;

Fig. 9 shows detached details.

My invention relates to a plug and socket for temporary connection of an electrical device such as an electric heater to a supply circuit of high potential. The entering portion of the plug, shown at 20 in Figs. 1 and 2, is rectangular in cross section with a rib 21 along one edge (see also Fig. 7) which prevents the entry of the plug in any posltion except the right one. The handle portion 23 'of the plug is round in cross section, except in the middle where it is oval. The body of the In is made of insulating material and it 'vi es transversely on the line w. Near the center of the entering part two metallic contact blocks 22 are inset, one on each of the opposite faces, and each block having its outer surface grooved transversely while the two are insulated by the body of the plug. The blocks or contact pieces 22 are smaller in area than the rein which the b ocks are inserted, the blocks bein thereby surrounded by an insulating sur ace extending to the tip or extremity of the plug.

Between the two separable halves of.the

plug is a cavity formin a connectionchamber in the top wall 0 which are two recesses each containing a screw-block connected by a rod 25 with one of the contact blocks 22. The upper half also has embedded therein two nuts 24, one of which projects out through the side of the plug to serve as a locking lug in a manner hereinafter described. Each of the nuts 24 receives a @erew 27 which extend longitudinally of the plug, passing up from beneath through a perforated projection or ofi'set on the inside of the metallic shell 28 which incloses the handle end of the plug. The

' screws 27 secure together the separable cross section of the entering portion of the plug. The exact shape of the box 30 is not material, so long as itsside walls at the ends of the slot fit the entering edges of the plug, to form a close fit therewith. The saidv entering portion of the plug is also of a width, in its wider dimension, equal to the interior width of the socket box 30 and of such length that, when fully entered, its tip will abut against the top wall of the box. By

this arrangement the entering portion of the plug, when fully inserted will form a complete wall or partition across the interior space within the box, leaving each contact block 22 in a separate chamber formed by the said partition. The interior width of the box in a direction transverse to, or at right angles to the thickness of the plug is greater than such thickness of the plug in order to provide the distinct chambers on either side of the plug when it is in place in the socket. In the two upper corners of the box 30 are two blocks of metal 32 screwed to the respective side-walls of the box, but exposed at the rear (as shown in Fig. 7) through-two openings in the rear wall of the box, where the circuit wires are attached to the respective blocks 32. Each block 32 carries a contact spring 31 bent at its outer or free end into a curved form to fit the grooved face of one of the contact blocks 22 on the plug. The said contact blocks 22, 1t will be observed, stand just inside of the slot through which the plug enters box 30, the extremity of theplug passing beyond the ends of the springs 31 to fit agalnst the top wall of the box as I have heretofore mentioned. By this means any are that may ocour, on the'withdrawal of the plug, between either of the blocks 22 and its correspondlng spring 31, will not be ablefito pass over the extremity of the plug to cause a sho rt-c1r-' cuit, but will be broken by the passing of the blocks 22 and by the surface of the plug which follows the blocks into the slot. -The arcing distance from the lower extremlties of springs 31 to the adjacent edge of the slot is far shorter than the arcing distance from one spring 31 around the extremity of the plug to the opposite spring 31, so that an arc which might form over the shorter dlstance would be extinguished before it had an opportunity to expand to a length that could bridge the longer distance.

The socket thus described I preferably inclose in a metallic casing 40 of similar shape Which is provided with a cover 41 hinged on rod 43 and normally held, by spring 42, in the position shown in Figs. 3 and 4, to cover over and close the slot through which the plug enters the socket. It is provided with out-turned lips 44 by which it may be grasped and turned into the position shown in Figs. 5 and 6 to permit the insertlon of the plug in'the' socket. Then a latch 45 on the inside of the cover 41 will snap under the locking lug 24 which I have heretofore mentioned and thereby lock the plug in position in the socket. The latch will'be maintained in position by spring 42 and can be readily released by drawing the cover 41 aside by means of the lips 44.

I What I claim as new and desire to secure .by Letters Patent is:

1. The combination with a socket member having an internal cavity provided with spaced apart internal contacts, a plug provided with a small contact block on each face of its entering portion, said entering portion being of a width equal to the internal Width of a cavity and of a thickness less than the transverse width of the cavity, whereby the entering of the plug into the cavity will divide the latter, into isolated, independent chambers, one contact of the socket and the corresponding contact of the plug being located in each chamber, the entrance opening of the cavity being smaller than the cavity to form a tight fit with the ug. p 3. The combination with a socket member having an internal cavity provided with spaced apart internal contacts, a plug provided with a small contact block in each face of its entering portion, said entering portion being of a width and depth equal to the internal width and depth of the cav- 'ity, and of a thickness less than the transverse width of the cavity, whereby the entry of the plug into the cavity will divide the same into isolated, independent chamhere, one contact of the socket and the corresponding contact of the plug being located in each chamber, theentrance opening of the cavity being smaller than the cavity to form a tight fit with the plug.

. 4. A plug of" insulating material formed in two parts separable on a line across the length of the plug, the meeting edges of the two parts being recessed to form a connection chamber, contact blocks on opposite faces of the entering part of the plug with a conductor extending from each block to the said chamber, a nut embedded in one of the two parts, and a screw passing longitudinally through the other part, the last mentioned part being longitudinally perforated to receive the conductor cord.

5. A plug of insulating material formed in two parts separable on a line across the length of the plug, the entering portion being of insulating material with a nut embedded therein, and the handle portion being also of insulating material and provided with an internal offset portion, a metal shell having a complemental internal offset portion, a screw passing through the offset portion of the metallic shell and the handle portion and entering the said nut.

6. A plug socket comprising a receptacle of insulating material provided with an internal cavity, one wall of which is provided with a narrow slot of less width than said cavity and equal to the interior length of the cavity, said slot being positioned to I cause the entering plug to engage the wall opposite the slot, whereby the interior space of the socket may be divided into two oppositely disposed parallel non-communicating distinct chambers.

7. A plug-socket in the form of a closed receptacle of insulating material provided wlth an internal cavity and having on one side a narrow guiding slot for the entry of the plug and spring contacts secured at points opposite said slot and adjacent the top of the casing and projecting to pointsv interior width of the socket, and socket-con tacts adjacent to said slot, of a plug having its entering portion of the same width and thickness as said slot and contacts on its opposite faces located back from the top thereof to engage the socket-contacts, whereby the entering plug will divide the interior of the socket into two distinct oppositely disposed parallel noncommunicating chambers containing respectively the contacts for the two sides of the circuit.

9. Thecombination with a socket, of a plug formed in two sections, a nut embedded in and pro'ecting laterally fromthe entering section 0 the plug, a screw in the handle section of the plug engaging the nut to-hold the plug sect1ons assembled, a casing 'inclosing the socket, and means carried by the casing for engaging the projecting portion of the nut to hold the gagement with the socket.

10. The combination with a socket of a plug in ena? plug formed in two sections, a nut embedded in and projecting laterally from the entering section of the plug, a screw in the handle section of the plug engaging the nut to hold the sections assembled, a casing inclosing the socket and provided with a hinged cover, and a latch carried by the cover for engaging the projecting portion of the nut to hold the plug 1n engagement with the socket.

11. In combination a socket having an internal longitudinally extending groove, contacts disposed in opposite portions of said In witness whereof I have hereunto set my hand, before two subscribing witnesses, this 24th day of February, 1912. 7

J S F. MCELBQY.

.v T A. Oaunnms, Cnannncn P.

45 socket, and a plug having an entering por- 

